These files are part of the dataset "County-level uncertainty statistics accompanying the historical settlement layers for the U.S. 1810 - 2015,"
contained in the dataverse �HISDAC-US: Historical Settlement Data Compilation for the United States� 
(https://dataverse.harvard.edu/dataverse/hisdacus).

Reference:
Leyk, Stefan; Uhl, Johannes H., 2018, "County-level uncertainty statistics accompanying the historical settlement layers for the U.S. 1810 - 2015," 
https://doi.org/10.7910/DVN/CXD9BW, Harvard Dataverse

Related Publication:
Leyk, Stefan; Uhl, Johannes H., 2018, "HISDAC-US: Historical Settlement Data Compilation for the Conterminous United States Over 200 Years," Scientific Data 5:180175
https://doi.org/10.1038/sdata.2018.175

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Corrigendum:

The spatial reference system used to project the layers was incorrectly described in version 1.0. This has been corrected in this new version (see below).
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This dataset contains the following files:
County_level_uncertainty.tar.gz with the shapefile Cnty_unc.shp that describes county-level uncertainty statistics to be used as accompanying information 
to the historical settlement raster layers contained in the datasets https://doi.org/10.7910/DVN/1WB9E4 and https://doi.org/10.7910/DVN/PKJ90M.

Cnty_Unc.shp is a county-boundary vector layer Cnty_Unc.shp with several county level uncertainty measures in the attribute table Cnty_Unc.dbf
with the following attributes: 
TMiss: Records with missing built-year per county (temporal)
GeoMiss: Records with missing geographic coordinates per county (spatial)
LUMiss: Records with missing land use attribute per county (thematic)
AMiss: Records with missing building area per county (thematic)
NumRecords is an additional field name  that presents the total number of records in a county and can be used to calculate proportions of missing records.

Data source: Zillow Transaction and Assessment Dataset (ZTRAX) (c) Zillow Inc.

Coordinate reference system:
USA Contiguous Albers Equal Area Conic USGS version (SR-ORG:7480)
https://spatialreference.org/ref/sr-org/usa_contiguous_albers_equal_area_conic_usgs_version-2/
Proj4: +proj=aea +lat_1=29.5 +lat_2=45.5 +lat_0=23.0 +lon_0=-96 +x_0=0 +y_0=0 +ellps=GRS80 +datum=NAD83 +units=m +no_defs

Contact:
Stefan Leyk
Department of Geography
University of Colorado Boulder
GUGG 110, 260 UCB 
Boulder, CO 80309-0260, United States of America
stefan.leyk@colorado.edu